In general, when a microcontroller is used to enable and protect certain types of electronic devices from over-temperature, a circuit pin on the microcontroller is coupled to a mainboard circuit of the electronic device for outputting an enable signal. Another circuit pin on the microcontroller is coupled to a thermistor for detecting an operating temperature of the electronic device. It can be known from the above content that in the conventional implementation, the microcontroller needs at least two physical lines to connect to the mainboard circuit and the thermistor, but this often results in difficulty in layout on a printed circuit board (PCB) for miniaturized design, and if the microcontroller fails, it will lose the function of over-temperature protection. Therefore, how to effectively reduce the PCB layout between the microcontroller and the mainboard circuit and maintain the original over-temperature protection function is indeed an issue that urgently needs to be solved in the field.